WO2023047792A1

WO2023047792A1 - Heater control system

Info

Publication number: WO2023047792A1
Application number: PCT/JP2022/028870
Authority: WO
Inventors: 啓史礒野
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2021-09-27
Filing date: 2022-07-27
Publication date: 2023-03-30
Also published as: US20240237148A1

Abstract

A heater control system (100) comprises: a resistance heater (1); and a step-up converter (2) that is electrically connected to the resistance heater (1). The step-up converter (2) outputs, to the resistance heater (1), a step-up voltage (V2) which is higher than the power-supply voltage (V1) of a power supply (3) that is electrically connected to the step-up converter (2).

Description

heater control system

The present disclosure relates to a heater control system that includes a heater that heats a seat or the like installed in a vehicle or the like, for example.

Patent Document 1 discloses a vehicle power supply device. This vehicle power supply device includes PWM (Pulse Width Modulation) means and detection means. The PWM means PWM-controls the electric power supplied from the vehicle-mounted power supply to an electric load such as a seat heater. The detection means samples and detects the voltage value of the vehicle-mounted power source in time series at a predetermined cycle. In this vehicle power supply device, the duty ratio of PWM control is determined based on the voltage value detected by the detecting means.

Japanese Unexamined Patent Application Publication No. 2010-95100

The present disclosure provides a heater control system that facilitates weight reduction while reducing costs.

A heater control system according to one aspect of the present disclosure includes a resistance heater and a boost converter electrically connected to the resistance heater. The boost converter outputs a boosted voltage higher than a power supply voltage of a power supply electrically connected to the boost converter to the resistance heater.

The heater control system of the present disclosure has the advantage that it is easy to achieve weight reduction while reducing costs.

1 is a perspective view of a seat equipped with a heater control system according to an embodiment; FIG. FIG. 2 is a diagram showing an outline of a heater control system according to the embodiment. FIG. 3 is a circuit diagram showing an example of a boost converter of the heater control system according to the embodiment. FIG. 4 is a flow chart showing an operation example of the heater control system in the embodiment. FIG. 5 is a diagram showing an outline of a heater control system of a comparative example.

According to this, it is possible to supply power equivalent to the rated power of the resistance heater even if a relatively small current is passed through the resistance heater, so there is a margin for increasing the resistance value of the resistance heater. . Therefore, when the resistance heater is a stranded wire, the number of stranded wires can be reduced compared to the case where the resistance value of the resistance heater is reduced. It is also possible to reduce the cost of manufacturing the That is, there is an advantage that it is easy to reduce the weight while reducing the cost.

In a heater control system according to another aspect of the present disclosure, the boosted voltage is twice or more the power supply voltage.

According to this, since the resistance value of the resistance heater can be made relatively large, even if the boost converter does not operate normally (for example, the boost converter has a short-circuit failure), the power supply voltage is applied to the resistance heater. , the current flowing through the resistance heater is greatly suppressed. Therefore, it is possible to reduce the possibility that the heater will overheat without providing a safety device such as a breaker, and there is the advantage that it is easy to achieve further cost reduction and weight reduction.

A heater control system according to another aspect of the present disclosure further includes a temperature detection unit that detects the temperature of the resistance heater. The boost converter controls the boost voltage based on the temperature detected by the temperature detector.

According to this, there is an advantage that it is easy to control the temperature of the installation location of the resistance heater with high accuracy.

In a heater control system according to another aspect of the present disclosure, the boost converter stops outputting the boosted voltage to the resistance heater when the temperature detected by the temperature detection unit exceeds a first threshold temperature. . The boost converter starts outputting the boosted voltage to the resistance heater when the temperature detected by the temperature detection unit falls below a second threshold temperature lower than the first threshold temperature.

According to this, the temperature at the location where the resistance heater is installed can be controlled simply by alternately repeating driving and stopping of the boost converter with the boost voltage set to a constant voltage, for example, compared to the case where the boost voltage is variably controlled. , there is an advantage that a separate voltage detection circuit is not required, and a simple configuration and control are sufficient.

In a heater control system according to another aspect of the present disclosure, the boost converter includes an inductance element, a first switching element, a second switching element, and a controller. The inductance element is electrically connected to the positive terminal of the power supply. The first switching element is electrically connected between the inductance element and the negative electrode of the power supply. The second switching element is electrically connected between the inductance element and the resistive heater. The controller controls on/off of the first switching element and the second switching element. The control unit controls to keep both the first switching element and the second switching element off, thereby stopping the operation of outputting the boosted voltage to the resistance heater.

According to this, by turning off both the first switching element and the second switching element, it is possible to cut off the electric path passing through the boost converter, so that the current does not continue to flow through the resistance heater, and the power consumption is reduced. It has the advantage of being able to reduce

In a heater control system according to another aspect of the present disclosure, the temperature detection section operates based on the power supply voltage. A first wiring that connects the temperature detection unit and the boost converter and a second wiring that connects the boost converter and the resistance heater are different systems.

According to this, even if an electric leakage occurs in one of the first wiring and the second wiring, there is an advantage that the possibility of electric leakage to the other wiring can be easily reduced.

In a heater control system according to another aspect of the present disclosure, the resistance heater is constructed by sewing a heater wire composed of a plurality of stranded wires.

According to this, even if the number of wires constituting the heater wire is reduced, it is easy to sufficiently secure the durability of the heater wire, so there is an advantage that the resistance value of the resistance heater 1 can be easily increased.

In a heater control system according to another aspect of the present disclosure, the resistance heater is configured such that the resistance value increases as the boost ratio, which is the ratio of the boosted voltage to the power supply voltage, increases.

According to this, it is possible to reduce the current value when heating the resistance heater with a predetermined power. Therefore, since the resistance value of the resistance heater can be increased, the number of twisted wires constituting the heater wire can be reduced. be.

In a heater control system according to another aspect of the present disclosure, the resistive heater is of a single type regardless of the heat generating power specification, and the boosted voltage is adjusted based on the heat generating power specification of the resistive heater. .

According to this, the same resistance heater can be easily adapted to various heat generation power specifications, so there is an advantage that it is not necessary to design a resistance heater according to the specifications.

Hereinafter, embodiments will be specifically described with reference to the drawings.

It should be noted that the embodiments described below are all comprehensive or specific examples. Numerical values, shapes, materials, components, installation positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the constituent elements in the following embodiments, constituent elements not described in independent claims will be described as optional constituent elements.

In addition, each figure is a schematic diagram and is not necessarily strictly illustrated. Moreover, in each figure, the same code|symbol is attached|subjected about the same component.

(Embodiment)
<Configuration>
1 is a perspective view of a seat equipped with a heater control system according to an embodiment; FIG. FIG. 2 is a diagram showing an overview of the heater control system 100 according to the embodiment. The heater control system is installed in the seat 1000 of the mobile body shown in FIG. The system consists of a cushion heater 11 arranged on a seat surface 1001 and a back heater 12 arranged on a backrest 1002.) heats at least a part of the user's body. The moving body is, for example, an automobile, but may be another moving body such as an airplane or a ship. As shown in FIG. 2 , the heater control system 100 includes two resistance heaters 1 , a boost converter 2 and a temperature detector 4 . Although the heater control system 100 includes the temperature detection unit 4 as a component in the embodiment, it does not have to include the temperature detection unit 4 as a component.

Each of the two resistance heaters 1 is a linear heater, and has a base material, a heater wire 10, and a sewing thread. The base material is made of a foaming resin such as cloth-like urethane formed in a sheet from a material having elasticity, flexibility and ductility. In addition, a nonwoven fabric may be sufficient as a base material. The heater wire 10 is a conductive wire that is electrically connected to the boost converter 2 via the connector 5 and the lead wire 6 (harness) and is capable of generating heat when a current flows from the boost converter 2 .

The heater wire 10 is sewn to one surface of the base material so as to return from the lead wire 6 for supplying power to the heater wire 10 through each part of the base material to the lead wire 6 . The heater wire 10 is a metal wire of copper or the like, and is composed of a plurality of twisted wires, and is sewn onto one surface of the substrate using, for example, polyester fiber thread as a sewing thread. The sewing thread is a thread for sewing the heater wire 10 to the substrate along the extending direction of the heater wire 10 in order to fix the heater wire 10 to the substrate. That is, in the embodiment, the resistance heater 1 is constructed by sewing a heater wire 10 composed of a plurality of stranded wires. Note that the heater wire 10 may be fixed to the base material by means other than the sewing thread, such as adhesion.

One resistance heater 1 of the two resistance heaters 1 is a cushion heater 11 installed on a seat cushion, which is a seat portion of the seat that supports the buttocks and thighs of the user sitting on the seat. Specifically, the cushion heater 11 is installed in the seat cushion between a pad corresponding to a cushion material and a cover covering the pad. The cushion heater 11 generates heat when power is supplied from the boost converter 2, and warms the user via the seat cushion.

The other resistance heater 1 of the two resistance heaters 1 is the back heater 12 installed in the seat back, which is the backrest supporting the back of the user sitting on the seat. Specifically, the back heater 12 is installed in the seat back between a pad corresponding to a cushion material and a cover covering the pad. The back heater 12 generates heat when power is supplied from the boost converter 2, and warms the user through the seat back.

The boost converter 2 is electrically connected to each of the two resistance heaters 1 via the connector 5 and lead wire 6 . In the embodiment, two resistive heaters 1 are connected in parallel to the boost converter 2 . Specifically, one end of each of the two resistance heaters 1 is electrically connected to the lead wire 6 and the other end is electrically connected to the ground 72 . The ground 72 is, for example, a chassis ground, but may be a common ground with the ground 71 on the power supply 3 side.

The boost converter 2 is a DC/DC converter, and has an input end electrically connected to the power supply 3 and an output end electrically connected to each resistance heater 1 via a connector 5 and a lead wire 6 . The boost converter 2 boosts the DC voltage input from the power supply 3 and outputs the boosted voltage to each resistance heater 1 via the connector 5 and the lead wire 6 . That is, the boost converter 2 outputs to each resistance heater 1 a boosted voltage V2 higher than the power supply voltage V1 of the power supply 3 electrically connected to the boost converter 2 .

The power supply 3 is, for example, an in-vehicle battery, and supplies electric power to electric devices such as the boost converter 2 and the like mounted on the moving object. In the embodiment, the power supply voltage V1 is ten and several volts, for example. Also, the boosted voltage V2 is several tens of volts, for example. That is, in the embodiment, the boosted voltage V2 is at least twice the power supply voltage V1. It should be noted that the upper limit of boosted voltage V2 is determined based on the power that boost converter 2 can output, for example. In the embodiment, the upper limit of the boosted voltage V2 is 48V as an example.

FIG. 3 is a circuit diagram showing an example of the boost converter 2 of the heater control system 100 according to the embodiment. As shown in FIG. 3, the boost converter 2 includes an inductance element L1, a first switching element SW1, a second switching element SW2, a capacitive element C1, and a control section 21.

The inductance element L1 has one end electrically connected to the positive electrode 31 of the power supply 3 and the other end electrically connected to the first switching element SW1 and the second switching element SW2.

The first switching element SW1 and the second switching element SW2 are semiconductor switching elements such as FETs (Field Effect Transistors), for example, and are controlled by the control section 21 to switch on/off.

The first switching element SW1 has one end electrically connected to the inductance element L1 and the other end electrically connected to the negative electrode 32 of the power supply 3 and the low voltage side terminal 52 of the connector 5 . That is, the first switching element SW1 is electrically connected between the inductance element L1 and the negative electrode 32 of the power supply 3. A negative electrode 32 of the power supply 3 is electrically connected to the ground 71 .

The second switching element SW2 has one end electrically connected to the inductance element L1 and the other end electrically connected to the capacitive element C1 and the high-voltage side terminal 51 of the connector 5 . That is, the second switching element SW2 is electrically connected between the inductance element L1 and the resistance heater 1. FIG.

The capacitive element C1 is electrically connected between the high-voltage side terminal 51 and the low-voltage side terminal 52 of the connector 5. A voltage across the capacitive element C1 is output to each resistance heater 1 via the connector 5 and the lead wire 6 as a boosted voltage V2.

The control unit 21 is an ECU (Electronic Control Unit) for controlling the two resistance heaters 1, for example. The control unit 21 controls ON/OFF of the first switching element SW1 and the second switching element SW2 by giving drive signals to the first switching element SW1 and the second switching element SW2, respectively.

In the embodiment, the control unit 21 can perform two operations: the boosting operation of the boost converter 2 and the stopping operation of the boost converter 2 . In the boosting operation, the control unit 21 performs PWM control to alternately turn on/off the first switching element SW1 and the second switching element SW2. That is, the control unit 21 turns off the second switching element SW2 when the first switching element SW1 is on, and turns on the second switching element SW2 when the first switching element SW1 is off. The first switching element SW1 and the second switching element SW2 are PWM-controlled. As a result, the boost converter 2 outputs a boosted voltage V2 obtained by boosting the power supply voltage V1 to each resistance heater 1 while the boosting operation is being performed. The boost ratio in the boost operation is determined based on the duty ratio in the PWM control of the first switching element SW1 and the second switching element SW2.

In the stopping operation, the control unit 21 controls to keep both the first switching element SW1 and the second switching element SW2 off, thereby stopping the output operation of the boosted voltage V2 to each resistance heater 1. . Which of the boosting operation of boosting converter 2 and the stopping operation of boosting converter 2 to be performed by control unit 21 is determined based on the temperature detected by temperature detecting unit 4, which will be described later. That is, in the embodiment, boost converter 2 controls boost voltage V2 based on the temperature detected by temperature detection unit 4 .

"Controlling the boosted voltage V2" here also includes controlling the boosted voltage V2 to be zero, that is, controlling the boost converter 2 to stop. Further, the boosted voltage V2 during the boosting operation of boost converter 2 is a constant voltage.

The temperature detection unit 4 is installed in the resistance heater 1 and detects the temperature of the installation location, that is, the temperature of the resistance heater 1 . In the embodiment, the temperature detection section 4 is installed in the cushion heater 11 of the two resistance heaters 1 . Note that the temperature detection unit 4 may be installed in the back heater 12 instead of the cushion heater 11 .

In the embodiment, the temperature detection unit 4 is a thermistor, one end of which is electrically connected to the control unit 21 of the boost converter 2 and the other end of which is electrically connected to the ground 71 . Since the control unit 21 operates by receiving power supply from the power supply 3 , the temperature detection unit 4 also operates by receiving power supply from the power supply 3 in the same manner as the control unit 21 . In other words, the temperature detector 4 operates based on the power supply voltage V1.

Here, the first wiring 81 connecting the temperature detection unit 4 and the boost converter 2 is supplied with the power supply voltage V1, and is supplied with a relatively low voltage. On the other hand, the second wiring 82 connecting the boost converter 2 and each resistance heater 1 is supplied with the boosted voltage V2, and is supplied with a relatively high voltage. Thus, in the embodiment, the first wiring 81 and the second wiring 82 are different systems. Therefore, even if an electric leakage occurs in one of the first wiring 81 and the second wiring 82, it is possible to reduce the possibility of electric leakage to the other wiring.

Next, an example of setting the resistance value of the heater wire 10 will be described.

A boost ratio K, which is the ratio of the boosted voltage V2 to the power supply voltage V1, is given by the following equation (1).

　　　　　K=V2/V1 (1)

The power W generated when the heater wire 10 generates heat is expressed by the following equation (2) using a resistance value R obtained by combining the resistance value of the cushion heater 11 and the resistance value of the back heater 12 in the heater wire 10. be

　　　　　W=V22/R (2)

From the equations (1) and (2), the resistance value R of the heater wire 10 is expressed by the following equation (3).

　　　　　R=K2・V12/W (3)

Here, when the necessary heat generation amount is determined, the power W is constant, and the power supply voltage V1 is the voltage of the power supply 3 (battery), so if it is assumed that it is constant, the resistance value of the heater wire 10 can be obtained from the equation (3) R is proportional to K2. Now, if the step-up ratio K is doubled, the resistance value R is 22=4 times.

Thus, based on the boost ratio K of the boost converter 2, the resistance value R can be obtained from the equation (3). At this time, the step-up ratio K is greater than 1 because it is premised on step-up. Therefore, the resistance value R obtained by the equation (3) becomes larger than when the step-up ratio K is 1. For these reasons, the resistance heater 1 is configured such that the resistance value R increases as the boost ratio K, which is the ratio of the boosted voltage V2 to the power supply voltage V1, increases.

<Action>
The operation of the heater control system 100 according to the embodiment will be described below with reference to FIG. FIG. 4 is a flow chart showing an operation example of the heater control system 100 according to the embodiment. Operation of the heater control system 100 is initiated, for example, when the user turns on the heater control system 100 .

The controller 21 repeats steps S1 to S4 while the heater control system 100 is in operation. That is, when the boost converter 2 is in the stopping operation, that is, when the boost converter 2 is off, each resistance heater 1 is in the off state, so the temperature detected by the temperature detector 4 (here, thermistor) is Decrease with the passage of time. Control unit 21 maintains the stop operation of boost converter 2 until the temperature detected by temperature detection unit 4 falls below the lower limit temperature (second threshold temperature) (step S1: No). On the other hand, when the temperature detected by the temperature detection unit 4 falls below the lower limit temperature (step S1: Yes), the control unit 21 starts the boost operation of the boost converter 2, that is, turns on the boost converter 2 (step S2). . As a result, each resistance heater 1 is turned on, and the temperature detected by the temperature detector 4 rises with the lapse of time.

Then, the control unit 21 maintains the boosting operation of the boost converter 2 until the temperature detected by the temperature detection unit 4 exceeds the upper limit temperature (first threshold temperature) (step S3: No). On the other hand, when the temperature detected by temperature detection unit 4 exceeds the upper limit temperature (step S3: Yes), control unit 21 starts stopping operation of boost converter 2, that is, turns off boost converter 2 (step S4). .

As described above, the control unit 21 repeats the boosting operation and the stopping operation of the boost converter 2 so that the temperature detected by the temperature detection unit 4 falls between the upper limit temperature and the lower limit temperature, thereby causing each resistance heater to 1 is repeatedly turned on/off. As a result, the temperature detected by the temperature detection unit 4 is maintained at a substantially constant temperature. By setting two different threshold temperatures, ie, the lower limit temperature when each resistance heater 1 is in the OFF state and the upper limit temperature when each resistance heater 1 is in the ON state, the on/off of each resistance heater 1 can be controlled. It prevents chattering. The temperature difference between the lower limit temperature and the upper limit temperature is, for example, 1 degree Celsius.

<Comparison>
Advantages of the heater control system 100 according to the embodiment will be described below in comparison with the heater control system 200 of the comparative example shown in FIG. FIG. 5 is a diagram showing an outline of a heater control system 200 of a comparative example. The heater control system 200 of the comparative example is different from the heater control system 100 of the embodiment in that the boost converter 2 is not provided and the heater control system 200 is provided with a control section 201 , an FET 202 and a breaker 203 .

The control unit 201 is, like the control unit 21, an ECU for controlling, for example, the two resistance heaters 1. The FET 202 is a field effect transistor and electrically connected between the positive electrode 31 of the power supply 3 and the connector 5 . The control unit 201 controls on/off of the FET 202 by giving a drive signal to the FET 202 . In the heater control system 200 of the comparative example, when the FET 202 is on, power is supplied from the power supply 3 to each resistance heater 1 through the connector 5 and the lead wire 6, thereby turning on each resistance heater 1 . When the FET 202 is off, the electrical circuit between the power supply 3 and the connector 5 is cut off, so that power is no longer supplied to each resistance heater 1 and each resistance heater 1 is turned off.

That is, in the heater control system 200 of the comparative example, instead of the boost converter 2 repeating the boost operation and the stop operation, the FET 202 repeats ON/OFF, so that the temperature is detected by the temperature detection unit 4 as in the embodiment. The temperature is maintained at a generally constant temperature.

The breaker 203 is electrically connected between the lead wire 6 and each resistance heater 1, and is configured to break the electric circuit when a current exceeding a predetermined magnitude continues to flow. This prevents excessive current from continuing to flow through each resistance heater 1 .

Here, in the heater control system 200 of the comparative example, since the boost converter 2 is not provided, the power supply voltage V1 of the power supply 3 is applied to each resistance heater 1 through the connector 5 and the lead wire 6 when the FET 202 is on. will be applied. Therefore, in order to supply power corresponding to the rated power (for example, several tens of W) to each resistance heater 1, a relatively large current i2 must be applied to each resistance heater 1. FIG. In order to pass a relatively large current i2 to each resistance heater 1, the resistance value of each resistance heater 1 must be relatively small. The current i2 referred to here is the sum of the currents flowing through the resistance heaters 1. FIG. Therefore, the current flowing through the cushion heater 11 and the current flowing through the back heater 12 are both smaller than the current i2.

As a means for reducing the resistance value of each resistance heater 1, it is conceivable to increase the number of stranded wires constituting the heater wire 10 of each resistance heater 1. There is a problem that the weight of the wire 10 is increased, and as a result, the weight of each resistance heater 1 is increased. Further, since the number of wires constituting the heater wire 10 is increased, there is a problem that the cost for manufacturing each resistance heater 1 is increased as a result.

Therefore, the heater control system 100 according to the embodiment includes the boost converter 2 to solve the above problem. That is, heater control system 100 includes boost converter 2 to apply boosted voltage V2 obtained by boosting power supply voltage V1 of power supply 3 to each resistance heater 1 via connector 5 and lead wire 6 . Therefore, in the heater control system 100 according to the embodiment, compared with the heater control system 200 of the comparative example, even if a small current i1 (<i2) is applied to each resistance heater 1, each resistance heater 1 can reach the rated power. It is possible to supply corresponding power. Further, since it is sufficient to supply a relatively small current i1 to each resistance heater 1, there is a margin for increasing the resistance value of each resistance heater 1 compared to the heater control system 200 of the comparative example. The current i1 referred to here is the sum of the currents flowing through the resistance heaters 1. FIG. Therefore, the current flowing through the cushion heater 11 and the current flowing through the back heater 12 are both smaller than the current i1.

Therefore, in the heater control system 100 according to the embodiment, there is no problem even if the resistance value of each resistance heater 1 increases. The number can be reduced. As a result, in the heater control system 100 of the embodiment, the weight of the heater wire 10 can be reduced as compared with the heater control system 200 of the comparative example, and as a result, the weight of each resistance heater 1 can be reduced. can. In addition, since the number of wires constituting the heater wire 10 is reduced, the cost for manufacturing each resistance heater 1 can be reduced as a result. As described above, the heater control system 100 according to the embodiment has the advantage that it is easy to reduce the weight while reducing the cost.

Further, in the heater control system 100 of the embodiment, depending on the boost ratio of the boost converter 2, the following advantages can be further enjoyed. That is, when boosted voltage V2 output from boost converter 2 is 1.5 times or more, preferably 2 times or more, power supply voltage V1, the possibility of the seat being overheated can be reduced without providing breaker 203. , there is an advantage that it is easy to achieve further cost reduction and weight reduction.

This is because, in the heater control system 200 of the comparative example, the resistance value of each resistance heater 1 must be relatively small. If this continues, each resistance heater 1 may become too warm. Therefore, in the heater control system 200 of the comparative example, the breaker 203 is provided to reduce the possibility of the seat being overheated.

On the other hand, in the heater control system 100 according to the embodiment, the resistance value of each resistance heater 1 can be made relatively large. Even if it continues to be applied, the current flowing through each resistance heater 1 will be even smaller than when the boosted voltage V2 is applied. From the above description, when the power supply voltage V1 becomes less than half the boosted voltage V2, the current flowing through each resistance heater 1 is greatly suppressed, so that each resistance heater 1 is prevented from overheating. Therefore, it becomes unnecessary to provide the breaker 203 .

In addition, in the heater control system 100 according to the embodiment, each resistance heater 1 is constructed by sewing the heater wire 10 composed of a plurality of stranded wires, so that the following advantages can be further enjoyed. That is, for example, if the heater wire 10 is a single wire and is not constructed by sewing, the heater wire 10 must be made thin in order to increase the resistance value of the heater wire 10 . In this case, if each resistance heater 1 is configured by pressing the thinner heater wire 10 to the base material, for example, without sewing, the heater wire 10 may bend due to the stress applied when the user sits on the seat. It is difficult to sufficiently secure the durability of the heater wire 10 .

On the other hand, in the heater control system 100 according to the embodiment, since each resistance heater 1 is constructed by sewing the heater wire 10 composed of a plurality of stranded wires, the resistance value of the heater wire 10 is Even if the number of lines is reduced in order to increase the size, it is easy to ensure sufficient durability against the stress applied by the user sitting on the seat. Therefore, the heater control system 100 of the embodiment has the advantage that the resistance value of the resistance heater 1 can be easily increased while sufficiently ensuring the durability of the heater wire 10 .

Note that the boost converter 2 has a characteristic that the boost voltage V2 can be adjusted. Only a single type of resistance heater 1 may be prepared. The heater control system 100 may be configured to meet the required heat generation power specification by adjusting the boosted voltage V2. A specific example of this will be described below.

First, from the equations (1) and (2), the electric power W when the heater wire 10 generates heat is expressed by the following equation (4).

　　　　　W=K2・V12/R (4)

Here, since the resistance heater 1 is of a single type, the resistance value R is constant. Also, as described above, since the power supply voltage V1 is constant, V12/R in equation (4) is constant, and the power W is proportional to K2. For example, if it is necessary to increase the calorific value (=power W) by 10% due to the required heat generation power specification of the resistance heater 1, if the step-up ratio K is approximately 1.05 times (=√(1+0.1)), good. Therefore, from equation (1), it can be seen that since the power supply voltage V1 is constant, the boosted voltage V2 should be adjusted to about 1.05 times the current value.

<Effect>
As described above, heater control system 100 in the embodiment includes resistance heater 1 and boost converter 2 electrically connected to resistance heater 1 . Boost converter 2 outputs to resistance heater 1 a boosted voltage V2 higher than power supply voltage V1 of power supply 3 electrically connected to boost converter 2 .

According to this, it is possible to supply electric power corresponding to the rated electric power of the resistance heater 1 only by supplying a relatively small current to the resistance heater 1, so the resistance value of the resistance heater 1 may be increased. leeway arises. Therefore, when the resistance heater 1 is a stranded wire, the number of wires can be reduced compared to the case where the resistance value of the resistance heater 1 is reduced, so the weight of the resistance heater 1 can be reduced and The cost of manufacturing the resistance heater 1 can also be reduced. That is, there is an advantage that it is easy to reduce the weight while reducing the cost.

Also, in the heater control system 100 according to the embodiment, the boosted voltage V2 is at least twice the power supply voltage V1.

According to this, the resistance value of the resistance heater 1 can be made relatively large. Even if the current is applied, the current flowing through the resistance heater 1 is greatly suppressed. Therefore, it is possible to reduce the possibility that the heater will overheat without providing a safety device such as the breaker 203, and there is an advantage that it is easy to achieve further cost reduction and weight reduction.

Further, the heater control system 100 in the embodiment further includes a temperature detection section 4 that detects the temperature of the resistance heater 1 . Boost converter 2 controls boost voltage V2 based on the temperature detected by temperature detector 4 .

According to this, there is an advantage that the temperature at the installation location of the resistance heater 1 can be easily controlled with high accuracy.

Further, in the heater control system 100 according to the embodiment, the boost converter 2 stops outputting the boosted voltage V2 to the resistance heater 1 when the temperature detected by the temperature detector 4 exceeds the first threshold temperature. The boost converter 2 starts outputting the boosted voltage V2 to the resistance heater 1 when the temperature detected by the temperature detection unit 4 falls below a second threshold temperature lower than the first threshold temperature.

According to this, the temperature at the location where the resistance heater 1 is installed can be controlled only by alternately repeating the driving and stopping of the boost converter 2 with the boost voltage V2 as a constant voltage. As compared with , there is an advantage that a separate voltage detection circuit is not required, and a simple configuration and control are sufficient.

Further, in the heater control system 100 according to the embodiment, the boost converter 2 includes the inductance element L1, the first switching element SW1, the second switching element SW2, and the control section 21. Inductance element L1 is electrically connected to positive electrode 31 of power supply 3 . The first switching element SW1 is electrically connected between the inductance element L1 and the negative electrode 32 of the power supply 3 . A second switching element SW2 is electrically connected between the inductance element L1 and the resistance heater 1 . The control unit 21 controls on/off of the first switching element SW1 and the second switching element SW2. The control unit 21 stops the operation of outputting the boosted voltage V2 to the resistance heater 1 by controlling to keep both the first switching element SW1 and the second switching element SW2 off.

According to this, by turning off both the first switching element SW1 and the second switching element SW2, the electric circuit passing through the boost converter 2 can be cut off, so that the current does not continue to flow through the resistance heater 1. , the power consumption can be reduced.

Further, in the heater control system 100 according to the embodiment, the temperature detection section 4 operates based on the power supply voltage V1. A first wiring 81 connecting the temperature detection unit 4 and the boost converter 2 and a second wiring 82 connecting the boost converter 2 and the resistance heater 1 are different systems.

This has the advantage that even if an electric leak occurs in one of the first wiring 81 and the second wiring 82, the possibility of electric leakage to the other wiring is easily reduced.

Further, in the heater control system 100 according to the embodiment, the resistance heater 1 is constructed by sewing the heater wire 10 composed of a plurality of stranded wires.

According to this, even if the number of wires constituting the heater wire 10 is reduced, the durability of the heater wire 10 can be sufficiently ensured, so there is an advantage that the resistance value of the resistance heater 1 can be easily increased. be.

Further, in the heater control system 100 according to the embodiment, the resistance heater 1 is configured such that the resistance value R increases as the boost ratio K, which is the ratio of the boosted voltage V2 to the power supply voltage V1, increases.

According to this, the current value when heating the resistance heater 1 with the predetermined power W can be reduced. Therefore, since the resistance value R of the resistance heater 1 can be increased, the number of wires constituting the heater wire 10 can be reduced, and the materials used for the resistance heater 1 can be reduced accordingly, and the cost and weight can be reduced. , has the advantage of

Further, in the heater control system 100 according to the embodiment, the resistance heater 1 is of a single type regardless of the heating power specification, and the boosted voltage V2 is adjusted based on the heating power specification of the resistance heater 1.

According to this, since the same resistance heater 1 can be easily adapted to various heat generation power specifications, there is an advantage that the design of the resistance heater 1 according to the specifications becomes unnecessary.

(Modification)
Modifications of the heater control system 100 according to the embodiment are listed below.

In the embodiment, the boosted voltage V2 is constant during the boosting operation of the boost converter 2, but it is not limited to this. For example, the boost voltage V2 during the boost operation of the boost converter 2 may be variable according to the rated power of the resistance heater 1 .

In the embodiment, the two resistance heaters 1 (cushion heater 11 and back heater 12) are both seat heaters provided on the seat, but are not limited to this. For example, the resistance heater 1 may be installed in the armrest of the seat or in the steering wheel.

Although two resistance heaters 1 are installed in the embodiment, the present invention is not limited to this. For example, three or more resistance heaters 1 may be installed, or only one may be installed.

Although the resistance heater 1 is a linear heater in the embodiment, it is not limited to this. For example, the resistance heater 1 may be a planar heater.

In the embodiment, the boost converter 2 is not limited to the configuration including two switching elements, that is, the first switching element SW1 and the second switching element SW2. A diode may be provided instead of the second switching element SW2. In this case, a switching element such as the FET 202 may be provided between the positive electrode 31 of the power supply 3 and the boost converter 2, and the stop operation of the boost converter 2 may be realized by turning off the switching element.

In the embodiment, the control unit 21 controls each resistance heater 1 by executing a series of flows as shown in FIG. 4 by software, but it is not limited to this. For example, the control unit 21 may implement a series of flows as shown in FIG. 4 by hardware.

In the embodiment, the resistance heater 1 is configured so that the resistance value R increases as the step-up ratio K increases. It is not limited. For example, the length of the resistance heater 1 may be lengthened to increase the resistance value R and widen the heat generation range. In this case, for example, if the predetermined power W is constant and the boost ratio K is 2, the resistance value R can be quadrupled. The heat generation range, which used to be limited to only one, can be extended to the sides of the seat with the same power as before.

It should be noted that the above embodiment can be realized by applying various modifications that a person skilled in the art can think of, or by arbitrarily combining the constituent elements and functions in the embodiment within the scope of the present disclosure. Forms are also included in this disclosure.

The present disclosure can be used, for example, to control a heater that heats a seat or the like installed in a vehicle or the like.

REFERENCE SIGNS LIST 1 resistance heater 10 heater wire 100 heater control system 1000 seat 1001 seat surface 1002 backrest 11 cushion heater 12 back heater 2 boost converter 200 heater control system of a comparative example 201 control section 202 FET
203 breaker 21 control unit 3 power supply 31 positive electrode 32 negative electrode 4 temperature detection unit 5 connector 51 high voltage side terminal 52 low voltage side terminal 6

lead wires

71, 72 ground 81 first wiring 82 second wiring C1 capacitive element L1 inductance element SW1 first switching Element SW2 Second switching element V1 Power supply voltage V2 Boost voltage i1, i2 Current

Claims

a resistive heater;
a boost converter electrically connected to the resistive heater,
The boost converter outputs a boosted voltage higher than a power supply voltage of a power supply electrically connected to the boost converter to the resistance heater.
heater control system.
The boosted voltage is at least twice the power supply voltage,
The heater control system of claim 1.
Further comprising a temperature detection unit that detects the temperature of the resistance heater,
The boost converter controls the boost voltage based on the temperature detected by the temperature detection unit.
A heater control system according to claim 1 or 2.
The boost converter is
When the temperature detected by the temperature detection unit exceeds a first threshold temperature, the operation of outputting the boosted voltage to the resistance heater is stopped;
when the temperature detected by the temperature detection unit falls below a second threshold temperature lower than the first threshold temperature, outputting the boosted voltage to the resistance heater is started;
4. The heater control system of claim 3.
The boost converter is
an inductance element electrically connected to the positive electrode of the power supply;
a first switching element electrically connected between the inductance element and the negative electrode of the power supply;
a second switching element electrically connected between the inductance element and the resistive heater;
A control unit that controls on/off of the first switching element and the second switching element,
The control unit controls to keep both the first switching element and the second switching element off, thereby stopping the operation of outputting the boosted voltage to the resistance heater.
5. The heater control system of claim 4.
The temperature detection unit operates based on the power supply voltage,
A first wiring that connects the temperature detection unit and the boost converter and a second wiring that connects the boost converter and the resistance heater are different systems,
5. The heater control system of claim 4.
The resistance heater is constructed by sewing a heater wire composed of a plurality of stranded wires,
A heater control system according to claim 1 or 2.
The resistance heater is configured such that the resistance value increases as the boost ratio, which is the ratio of the boosted voltage to the power supply voltage, increases.
A heater control system according to claim 1 or 2.
The resistance heater is of a single type regardless of the heating power specification,
wherein the boosted voltage is adjusted based on the heat generation power specification of the resistive heater;
A heater control system according to claim 1 or 2.